Work is in progress to understand the genetic and molecular basis of regulation of the amylase system of Drosophila pseudoobscura. This system includes the structural gene Amy and its associated, presumptive control genes. Two types of control genes are being studied: regulatory genes which control the amount of amylase present and temporal genes which control the tissue specific expression of Amy in time. The first part of the research has focused on the biochemical characterization and purification of the amylases coded for by the Amy1.0 and Amy.84 alleles of the fly and a plasmid/Escherichia coli system which has had the Amy1.0 gene cloned into it. The second part of the research is directed at isolating genetic strains which possess different control genes. Finally, another part of the research is concerned with the development and dietary aspects of regulation.